Will carbon fiber cure Apple’s iPhone 5 Scuffgate headache?

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In the quest for lighter and larger phones, Apple moved (back) to aluminum for its new iPhone 5. The result is a sleek, featherweight design with one problem: it’s easy to scratch. Whether or not the criticism is fair, complaints are taking on a life of their own among iPhone 5 owners, and has been dubbed “Scuffgate” by the press. Better anodization may be a solution, but Apple has quietly been working on another option — carbon fiber — for several years now.

As early as 2009 Apple’s carbon fiber guru, Kevin Kenney, filed for a patent on a reinforced phone case that could be a plastic composite stiffened with a carbon-fiber-reinforced plastic (CFRP) spine. Cyclists may recognize Kenney as the former CEO of pioneering carbon-fiber bicycle maker Kestrel.

Carbon fibers’ light weight and unusual strength make them a natural stiffener for fast bike frames, as well as camera tripods, race cars, and airplanes. The carbon fibers themselves are three times lighter and four times stronger than steel.

Why it hasn’t happened yet

Cost is often cited as a reason carbon fiber hasn’t found its way into more consumer devices. That’s too simple an explanation however, especially considering that some phones cost nearly $1,000 unlocked — plenty of room to spend a few more dollars on a chassis. Carbon fiber presents several challenges in a phone, tablet, or laptop design. First among them is its low melting point, which makes CFRP difficult to machine or drill without deforming.

As a result, CFRP is best suited for single pieces that can be molded with minimal connection points, like the glued together pieces of a carbon-fiber bicycle frame. The back side of a phone is certainly a candidate. In fact, there are already iPhone protective cases that use a flat sheet of CFRP to help protect the phone from drops and scratches.

Unfortunately, the issues with CFRP don’t stop with getting it into shape. It has very low thermal conductivity, making it ideal for items like camera tripods that need to be handled in cold weather. Phones and computer cases, though, need to bleed off heat generated by their electronics. CFRP chassis, like plastic ones, need a separate heatsink, precluding designs like the new Macbook, which relies on its aluminum unibody for cooling.

Coincidentally carbon fiber, like plastic, is not an EMI shield, so to avoid bleeding electronic noise into the world any CFRP phone could use its metal EMI shield as a heatsink. The only problem is that the metal shield adds back some of the weight that using carbon fiber is designed to reduce.

CFRP is also almost the opposite of aluminum or steel in many ways. It is remarkably stiff, which is great for protecting what’s inside from denting or bending, but once it reaches its limits it breaks rather than yielding. That means a CFRP chassis would need to be over-spec’d compared to a similar metal version.

Did Android already beat Apple to the punch?

For those keeping score in the interminable war between Apple and Android, they’ll be happy to know that there is already an Android phone with a partial carbon fiber chassis. Tag Heuer introduced the very-cool looking, and very-expensive Racer phone earlier this year. At a little over $3,000, it isn’t flying off the shelves, but I’m sure they’re more than covering the cost of working with the material.

Kevlar would be a better choice so would spectra cloth and Kenny should know that a better product would be a boron/spectra hybrid weave. it would take way more instant impact or point impact then CF and would be MUCH stronger overall then pure CF. Heat is no issue as they make booster nozzle’s from CFRP and t’s just a matter of picking the right resin, UV drying, ( yellowing) is an issue if your opting for the ‘bare’ look.

Spectra cloth sounds very cool, but from what I’ve read doesn’t seem to have made it into consumer electronics cases. Any idea if that is because of its potential susceptibility to creep, or just cost+process issues?

Good point about Kevlar. I know it is tough enough (armor, RAZR backplate, etc.). Can it be made stiff enough to do an entire case (with attachment points for the display, resistance to torsion, etc.)?

I have to admit, that part was mostly tongue-in-cheek, but it is one of the first uses of CF that I found in a phone chassis. CF is sometimes used to stiffen PCB boards, so it may have found its way into some phones that way.

jescott418

I find it very amusing how Apple fans spend money to protect their beautiful yet fragile iPhone. Its a case again of where Apple’s form does not meet function. Its like their aluminum case laptops. which at one time were so attractive yet so dent magnets.

some_guy_said

@DavidCardinal:disqus You know why carbon fiber has many of the same properties as plastic? Because it is carbon fiber, infused with an epoxy resin…which is plastic.

And plastic can scuff, just like metal. getting a carbon fiber case doesn’t change that, it just makes the person holding the phone look like a giant d-bag.

The reason why it is difficult to machine is not because “it” has a low melting point, it is because the epoxy plastic resin has one melting point, whereas the carbon fiber has a much higher melting point, and is much stronger. Machining it would be very irregular due to the heterogeneous nature of the material.

@facebook-507269607:disqus The nature of the issues you are trying to solve with different fibers are caused by the resin used, not the fiber. So changing out the different fibers for kevlar or spectra will not make any difference…

You can always buy a carbon fiber backing for your iphone 5. Disclaimer: I make one you can buy at amazon (dba cases)

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